Theoretical and experimental research is to be carried out on phase change phenomena in fluids with retrograde equations of state, and on phase changes induced by shock waves to produce conditions near the critical point in fluids with conventional equations of state. The phenomena to be explored are expansion shocks, liquefaction shock stability, shock splitting, and ring- vortex formation. Potential application areas include fuel injection systems and fire and explosion technology, as well as phase change phenomena in the flow of heavy fluids such as fluorocarbons. //